Author Topic: Tyre wear question (Read 7020 times)

2bikebill · **on:** July 08, 2011, 05:15:27 pm

Just fitted a new rear tyre. I'm wondering why the rear has worn out after less than 4000 miles, while the front, fitted at the same time, has got loads of tread left on it.....?
These are AM26 RoadRiders on a G5, which I don't go slow on. But no wheelies....

Vince · **Reply #1 on:** July 08, 2011, 05:27:13 pm

There is another thread going about tire pressures right now. Not mentioned there is how pressure affects wear. Too much pressure makes a smaller contact patch, so wear is accelerated at that point of road contact. Too little pressure causes the tire to squirm. The excess heat generated from this squirming burns off tread.
Tire pressure is a compromise between wear, handling, and tread life. Optimize one and the others will suffer. The trick is finding a tire pressure that offers acceptable performance in all areas.

2bikebill · **Reply #2 on:** July 08, 2011, 05:36:38 pm

I did wonder about pressures. At the recommended pressures - 18psi front & 28psi rear, there's quite a difference between them. It's the centre grooves on the rear which have worn right down to the tread wear indicators, so I guess the higher pressure in the rear tyre explains it. Still - doesn't seem like enough miles for my money..... $:-\$

singhg5 · **Reply #3 on:** July 08, 2011, 07:26:15 pm

@Will:

This is the fault of you wanting speed, using 18 tooth FD sprocket to zooooommm and torque on the rear tire (gee, now I have to spell it again, TYRE) - that did it

!

Don't tell me, that you have changed to 17T

.

2bikebill · **Reply #4 on:** July 08, 2011, 07:33:11 pm

Yes I changed back to the 17t sprocket. The bike was just too chug chug chuggy with the 18t. Nice for sustained long distance rides, but I didn't like it for normal mixed local riding after all, which is mostly what I do on the old thumper.
Not as much as you though - you''ll be up to six figures on that thing soon...

singhg5 · **Reply #5 on:** July 08, 2011, 07:48:25 pm

What do you think of switching back to OEM Avon Speedmaster rear tire ?

I have 15K on the same rear tire, since I bought the bike 2 years ago - not bad at all ! I should add that the front tire did not last as long as the rear one and was replaced once.

2bikebill · **Reply #6 on:** July 08, 2011, 08:08:24 pm

15K! That's impressive! I think you must be treating your bike with the greatest respect Singh.
I still have the original tyres hanging on a hook in the garage, but I doubt I'll go back to them. I really like the way the bike handles with the RoadRiders - great cornering and good grip wet or dry. I don't mind sacrificing a bit of longevity for such benefits - but less than 4000 miles seems a bit excessive!
I'm hoping the front & rear will wear out together next time so I can try something different...

barenekd · **Reply #7 on:** July 08, 2011, 08:27:19 pm

Back in the GOD (Good Ol Days) I used to figure about two rear tires for one nose wheel.
Nowadays, the ratio is closer to one to one. In fact, I've had rear tires outlast the front on some sport bikes.
Bare

Andy · **Reply #8 on:** July 08, 2011, 10:28:02 pm

I have 17,000 km on my Roadriders. The rear is looking shabby, but it still has life in it. I think you got gypped, Will.

2bikebill · **Reply #9 on:** July 08, 2011, 11:11:54 pm

I'm obviously doing something very wrong, or you guys are riding on tyres which would be illegal in UK, or you're riding like pussies.... $:-\$
When you say shabby - how is the centre tread? Are you running on tyres that are bald in the middle?
Tyre regulations here stipulate:
1.The grooves of the tread pattern must have a depth of a least 1 mm throughout a continuous band measuring at least three-quarters of the breadth of the tread and round the entire outer circumference of the tyre, OR
2.if the grooves of the original tread pattern of the tyre do not extend beyond three-quarters of the breadth of the tread (i.e. common with motorcycle tyres) any groove of the original pattern must have a minimum depth of at least 1 mm.
The centre groove on my rear tyre is worn down to the indicator - 1mm depth. The rest is fine.
And I'd pay a fine if I was caught on it

singhg5 · **Reply #10 on:** July 08, 2011, 11:56:23 pm

Quote from: WillW on July 08, 2011, 11:11:54 pm

I'm obviously doing something very wrong, or you guys are riding on tyres which would be illegal in UK

how is the centre tread? Are you running on tyres that are bald in the middle?

I think you are thinking on the right track about riding on tires with no tread - that would be illegal in UK.

Only after reading what you wrote, did I remember that my G5's front tire had gone so bald that nobody could find where the depth indicator was

. Actually we thought it does not come with an indicator - until the new tire came and to our delight & surprise it had an indicator that was visible. So I must have been riding way way past that mark that there was no sign of it ever existed !!

But the rear tyre is like a tractor tire - very deep tread, so it stays. Only it is beginning to show very small cracks on the side.

barenekd · **Reply #11 on:** July 08, 2011, 11:58:10 pm

The Man doesn't say too much about tire wear in the US. I'm not aware of any laws that stipulate anything about tread depth. There are a lot of safety bulletins around about it, though. I have been known to take them to the cord on rare occasions. In fact, one of them was purely accidental. I'd been watching the rear tire as it was close, but ignoring the front because they always last longer. A friend pointed out the rather bare treaded front tire to me. Oops, I took it immediately to the dealer.
Bare

Maturin · **Reply #12 on:** July 09, 2011, 12:10:39 am

I guess I could do some 20´kms on the SafetyMileage, too. This is a tough tyre. The only, but decisive disadvantage is the squared threat and the subsequently decreasing cornering ability of the aging tyre. Adhesion is quite fine as long it´s not weat. If it wasn´t shaped like a tetragon there wouldn´t be any reason to use something different.

The worn threat in the middle of your Roadrider, Will, indicates either too much Autobahn or too much pressure. I had the same problem with the stock Speedmaster in the front after 6500kms, because I had 25-30 dpi in it. The result was a flat middle profile, whereas the flanks were still quite opulent.
Try to lower the pressure a bit, maybe this will prolong the tyre´s life. But as long the rubber keeps your bike on the road under all circumstances, it´s possibly worth to change it frequently.

2bikebill · **Reply #13 on:** July 09, 2011, 07:42:12 am

I really dislike that square profile of the Speeedmaster rear tyre, and I hated the handling quirks of the ribbed front one - goes where it likes on grooved surfaces, and deadly on white lines. The thing about retro-looking tyres is, they tend to behave like retro tyres....
Mostly twisty roads where I live, and like most of us, I love that kind of riding. As soon as I fitted the RoadRiders the difference in handling was immediately apparent - the bike practically steers itself and will really hang into the curves. Feels much more planted to the road, wet or dry.
I've now put them on the Kawa too. Improved, but not quite so radically - but then it didn't start out with anything quite as obsolete as the Skidmeisters....

I don't skimp on tyres, not with four wheels and particularly not with two! There's not a lot where rubber meets road so it wants to be as good as it can be. Experience & technique amount to bugger all once the grip lets go half way round a fast curve .....

I figured some of you must be riding on death-trap tyres..... 10,000 miles on a motorbike tyre that's still roadworthy....?? Nooo I don't think so....
Riding on bald/old/cracked tyres for the sake of a few quid is dumb on four wheels - on two it's suicidal. Chuck em - your life depends on it. Literally.

Maturin, I don't do much trunk road riding, and I stick to the recommended pressures - 28 psi rear. Tried it a bit lower but didn't like it. The front is at 18psi, which seems too low doesn't it, but works fine on the Enfield. Again, I tried higher, but it felt a bit twitchy. The strange recommended pressures do seem spot on for these bikes, but yes, there is a big difference between front & rear, and this I guess must contribute to faster wear at the back.

Andy · **Reply #14 on:** July 09, 2011, 10:14:39 am

Well, I won't say it may not have been a factor in my unfortunate incident in the rain last May, but the tire ain't all that bad. I'll shoot a pic and post it.

Maturin · **Reply #15 on:** July 09, 2011, 11:16:39 am

Quote from: WillW on July 09, 2011, 07:42:12 am

I don't skimp on tyres, not with four wheels and particularly not with two! There's not a lot where rubber meets road so it wants to be as good as it can be. Experience & technique amount to bugger all once the grip lets go half way round a fast curve .....

+1

Blue Ridge Wheeltor · **Reply #16 on:** July 09, 2011, 03:49:50 pm

So I bought a pair of K70's for the '72 Bonneville (3.50x19 and 4.0x18) and got the front mounted. I am putting the Bonnieback on the road, but it is slow going and will sell it.
Now I am starting to think, maybe swap the avon and K70 between the Triumph and Enfield front and buy a 3.50x19 for the rear. This will leave me with a useless 3.50x19 avon speedmaster, unless the sidewall is ated strong enough to use on the sidecar of the Ural. What do you think?
And while we are at it, why do some sites list front tire and back for the K70, and some sites indicate they are interchangeable?
Does the K70 make enough of a difference to go through the hassle? Money is tight, but our roads are twisty.

olhogrider · **Reply #17 on:** July 09, 2011, 04:35:41 pm

The Dunlop website shows the 3.25 is front only, the 3.50 is front/rear and the 4.00 is rear only. I have no idea why.

barenekd · **Reply #18 on:** July 09, 2011, 07:59:56 pm

The 3.25/3.50 tires are set up for WM2 rims. The 4.00 is set up for the wider WM3.
Bare

Andy · **Reply #19 on:** July 10, 2011, 01:29:54 pm

Quote from: WillW on July 09, 2011, 07:42:12 am

I figured some of you must be riding on death-trap tyres..... 10,000 miles on a motorbike tyre that's still roadworthy....?? Nooo I don't think so....
Riding on bald/old/cracked tyres for the sake of a few quid is dumb on four wheels - on two it's suicidal. Chuck em - your life depends on it. Literally.

No picture yet, but you made me paranoid, so I gave them a good look-see. The rear is just getting down to the wear indicators. By 20,000 km they should be junk. Which is unfortunate, because I can't afford new rubber this year, so I guess I don't get to finish the season.

2bikebill · **Reply #20 on:** July 10, 2011, 03:07:39 pm

Andy - is that the centre groove wear indicator, or the sides - with the centre groove gone completely? I'm genuinely baffled how you can get over 10000 miles on the rear tyre (AM26, yes?). What pressure do you have? How do you ride?

Andy · **Reply #21 on:** July 10, 2011, 06:42:00 pm

Oferchrissakes, lemme get the camera....

t120rbullet · **Reply #22 on:** July 10, 2011, 06:48:25 pm

Tires in the US have small arrows on the sidewall pointing to where the wear bars are.

Andy · **Reply #23 on:** July 10, 2011, 07:08:00 pm

There's 16,800 km on the odo and at least another thousand that I rode with a broken speedo cable. You can see the wear bar on the top pic.

Maturin · **Reply #24 on:** July 10, 2011, 07:35:50 pm

Hey Andi!
You can even get a Bridgestone Battlax BT-45 for your C5!

http://www.motorcycle-superstore.com/1/28/396/6013/ITEM/Bridgestone-Battlax-BT-45-Sport-Touring-Rear-Tire.aspx
77 bucks! I wish there were some in 19´...

But there are low-price options, too:
http://www.motorcycle-superstore.com/2/29/393/15130/ITEM/Kenda-K761-Dual-Sport-Rear-Tire.aspx
53 pieces of paper.
Unfortunately Mitas is hard to get over there in north America, otherwise this would be my no.1 price tip. They cast some decent tyres there in Czechia...

2bikebill · **Reply #25 on:** July 10, 2011, 08:51:00 pm

Thanks for posting the pic Andy. That's an illegal tyre where I come from. I wouldn't ride on em - skiddy in the wet and thin for punctures......

My rear AM26 was down to the limit - the indicator level with the rubber either side, that's 1mm depth left on the centre groove - after 3,500 miles! You must be riding like a steady old gent on roads made of the finest silk

Maturin - those BT45s are good tyres. I wanted them for my W650 but there was a long wait so I got the RoadRiders. But I'll be getting them next time - which wont be long judging by the way I seem to wear em down...

Arizoni · **Reply #26 on:** July 10, 2011, 09:01:43 pm

Andy
The real "wear bar" is the horizontal thing in your picture and it isn't worn at all.

Hell, you might even have 0.005 worth of tire tread sticking up above it.
That ought to be good for another 1000 miles don't you think?

Seriously you ought to start looking for some new tires.

They are damn cheap insurance against getting some severe road rash on your bod and as good as the Royal Enfields warranty is it doesn't cover torn up motorcycle parts that got that way from sliding on the tarmac.

Andy · **Reply #27 on:** July 10, 2011, 10:09:23 pm

Oh, there are inexpensive tires out there, I know. I can't afford those either. I was out of work for several months last year, and I refuse to live off the dole, so I"m skint. I'm living paycheque to paycheque until I can get caught up.

Would you know, there's a not a single Avon Roadrider to be had in this country. RE hasn't brought any in yet. Not that I'd put them on again anyway. They're great on asphalt, but horrible on gravel, dirt and mud - and I tend to seek out gravel, dirt and mud with some frequency.

When I do get new rubber on, it'll be the Dunlop K70s or equivalent. I like the look of them and I like the thought of this being "on rails".

To answer, "How do I ride?" I ride from one place to another. If it's twisty, it's twisty, if it's straight, it's straight. I don't go thrill-seeking. If I had ready access to a track, I'd do dangerous, hair-raising things, but I won't do it on a road. Most of my journeys are in the 80-100 km/h zone, with brief forays into the 110-120 range. I never run it more than fifteen minutes at those higher speeds.

As for pressure, I ran several thousand K on the pressure the dealer put in - the one printed on the frame, then dropped it to the lower pressures in the owners manual, plus a pound or two. Currently I'm running 19 psi front, 25 rear.